The invention relates to a device for the manufacture of tablets or compacts in accordance with at least two compacting tools which, in each case, can be moved in relation to one another and at least one template interacting with these and with filling means to feed the tabletting material into the template.
Automatic devices for the manufacture of tablets are based on the principle that a tabletting material is pressed to a tablet by means of a compacting process. For this purpose, two moving punches serve as compacting tools. Known automatic devices for the manufacture of tablets possess a bottom punch in vertical alignment which works in a template and a top punch which is led into the template only for compacting. The top punch slides into the template, pushes the powder together and compacts the tablet. The thickness, firmness and compacted gloss of the tablet depend on said top punch and its compacting pressure. The depth of insertion and the amount of pressure can be adjusted. The bottom punch is located in the template. It limits the pot towards the bottom. During the compacting process it as a rule forms the pressure sustaining part. At the end of compacting, it is led upwards and so moves the tablet to the template edge where it is pushed to the side. In the next cycle, the bottom punch returns to its start position and the template pot is ready to accept the next filling. The filling of the template is performed via a filling funnel whose bottom part is termed a filling shoe.
These known devices are as a rule today designed as concentric tabletting machines. In these types, the filling shoe of the filling funnel is stationary while the template is movable. A round horizontal plate supports a number of templates. As described above, each template has its own top and bottom punch. The punches are raised or lowered via rollers. By turning a horizontal plate, the templates are moved one with their punches after the other into the position ready for filling underneath the filling shoe.
Concentric tabletting machines possess a number of serious defects due to their process technology which cannot be eliminated completely due to the design principle of the device described above. Here, the following disadvantages are of most significance in the manufacture of tablets for pharmaceutical purposes or also of compacts in the food sector:
An intensive pre-treatment of the substances to be compacted is necessary in order to obtain good flow behavior and dosing capability. PA1 The filling principle (fixed filling shoe on a rotating template table) means that relatively high material loss has to be accepted and that, for example, metal rubbings enter into the product to be made through the seal rails to be provided on the filling shoe. The so-called black spots are created on the table surface. PA1 Dust created in the compacting pot of the device is first deposited on the free surfaces of the greased top punch. As the process continues, it falls off and enters into the filling shoe through the template table. This effect also leads to the already mentioned "black spots" on the tablet surface.